public class Test {
    public static int jiChenSum(int n) {
        int num = 1;
        int sum = 0;
        for (int i = 1; i <= n; i++) {
            for (int j = i; j >= 1; j--) {
                num *= j;
            }
            sum += num;
            num = 1;
        }
        return sum;
    }
    public static void main(String[] args) {
        System.out.println(jiChenSum(10));
    }
}
